Book ~ "The Second Wife" (2011) Brenda Chapman

From Goodreads ~  Gwen Lake is a forty-five-year-old police officer with a desk job, an ex-husband and a future not even close to the American dream. 

A year after her divorce, and more out of boredom and curiosity than anything else, she agrees to a meeting with her ex's new wife. She has no idea that the encounter will lead to murder. And she has decidedly mixed emotions when her ex-husband is arrested for the crime. 

Instead of accepting the lead detective's advice to book a Club Med vacation and leave the investigation to the professionals, Gwen decides to work the case on her own. Her life is about to get a lot less predictable and a lot more dangerous.

Gwen Lake is a cop but the chief of police has her in a desk job because she has a great memory for numbers and information.  She's in her mid-forties and her husband, Brian, recently left her for someone else.  When Marjory, the new wife, wants to meet her for a coffee, Gwen agrees out of curiosity.  Marjory tells Gwen that she is scared of Brian, which Gwen scoffs at since he is a mild-mannered shoe salesman.  Marjory then turns up dead and Brian is arrested for her murder.  Gwen is the only one who believes in his innocence and it's up to her to prove it.

I've read a few books by this author and I liked this one.  It's a quick read at less than 100 pages and moves at a quick pace.  I like this author's writing style.  It is written in first person perspective in Gwen's voice.  There is some swearing.